1. Field of the Invention
This invention relates to a process and apparatus for simplified document editing before printing in a reprographic system.
2. Description of Related Art
It is desirable to edit a document before it is printed using an electronic reprographic system, especially when using color capable systems. Normally, a document is placed face-up on an edit pad or on top of the platen cover, marked with an editing pen and then at least turned face-down or registered on the platen for copying. Thus, after editing, the operator must register the edited document on the platen.
Therefore, the conventional editing method requires that the operator handle the document at least twice. This extra handling of the original document is time consuming and could cause the document to be misregistered on the platen, thereby introducing needless errors when copying.
Further, the objective of most editing operations is to designate areas of the document copy which the operator wishes to be altered or modified in a designated manner. Such areas are marked with an editing pen designed for this function. The editing pen may be passive, i.e., cordless (though still attached to the device in order to preserve unit integrity) or active, i.e., connected to the copier or edit pad by an electrical cable.
The operator first activates the particular editing function (e.g., delete, change color to red, or another similar instruction) and subsequently touches the document with the editing pen in a prescribed manner. For instance, in a common editing function, the operator touches the upper left corner and lower right corner of a rectangle within the document to be copied, thereby defining a rectangle in which the editing function may be implemented.
For editing a document, there is usually a reserved area, (i.e., an edit pad) on the top of the reprographic printing system, near the platen cover or on the platen cover itself. It may also be a separate device, electronically linked yet set apart from the reprographic system.
In order to define reproducibly the document position, the document must be placed on the edit pad in a defined manner, i.e., registered. This is true of most known editing devices and usually consists of placing the document on a rectangular grid, against protruding stops, with the lower left corner at a designated mark. The edit pad area contains devices which are capable of detecting the position(s) of the editing pen and forwarding this data, for further processing, to the reprographic system controller to modify accordingly the document copying instructions.
Some examples of edit pad technology known in the art include:
1) An edit pad that comprises an array of electrically resistive wires in the X direction overlayed by another such array in the Y direction. Periodically located spacers prevent unintentional contact between the X and Y wires. A flexible, electrically insulative sheet covers this wire grid and represents the edit pad surface. Pressing the cordless editing pen against the document causes contact between the X and Y wires at that location. The processing unit is then capable of calculating X,Y coordinates of the contact point from the resistances of the segments of the contacting wires.
2) In another device, the X and Y wire grid is found as above, however, in this device the reprographic system controller broadcasts electrical pulses sequentially (i.e., into the nth wire, then the n+first wire, and so on). The active editing pen acts as an antenna and the receiver correlates the received pulses with the coordinates of the specific X and Y wires (based on, for instance, timing of the pulses). The detection algorithm places the editing pen at the wire from which the received signal is the strongest and compares it with the signals from neighboring wires and then calculates the position with high accuracy. Clearly, this editing technique would not work with an electrically conducting original document because of the electrical screening of the pen.
3) In still another technique, an active pen that emits a sound when pressed against the original document is employed. The microphones placed on the edit pad periphery receive the sound and calculate the microphone-to-pen distance in a manner similar to that of an active sonar system. The controller then calculates the X and Y coordinates of the pen by triangulation.
4) Finally, some color capable reprographic systems which are capable of differentiating document colors, utilize actual color pen editing. That is, the operator circles with a "red pen" that portion of the document he wishes printed in red. When the document is scanned by the copier, the image processing unit recognizes the red mark and renders the marked document portion in red.
It should be understood that any of the above-described methods of document editing are applicable to the invention described herein. In addition, all similar editing procedures not discussed above are equally applicable for use with this invention.